The use of the activating supports, in particular with metallocene catalysts, provide advantages for operation in both gas and slurry phase processes for the polymerization of ethylene or the copolymerization of ethylene and α-olefins having from 3 to 10 carbon atoms.
In recent years there have been many advances in the production of polyolefin homopolymers and copolymers due to the introduction of single site catalysts such as metallocene catalysts. Metallocene catalysts offer the advantage of generally a higher activity than traditional Ziegler catalysts and are usually described as catalysts which are single site in nature.
The above single site catalyst systems such as metallocene complexes may be used for the polymerization of olefins in solution, slurry or gas phase. When used in the slurry or gas phase the metallocene complex and/or the activator are suitably supported. Typical supports include inorganic oxides eg. silica or polymeric supports may alternatively be used.
Examples of the preparation of supported metallocene catalysts for the polymerization of olefins may be found in WO 94/26793, WO 95/07939, WO 96/00245, WO 96/04318, WO 97/02297 and EP 642536.
The above supported polymerization catalyst systems may in some cases lead to certain disadvantages such as cost, instabilities as well as poor morphology of the resultant polymers as well as problems with gels and the like when subsequently transformed into films and other articles.
In recent years attempts have been made to replace the activator or cocatalyst components of the supported polymerization catalyst systems by use of activating supports.
EP 906920 describes fluorine-containing activator solid supports for metallocenes wherein the surface of the support has been modified by aluminium (or magnesium) Lewis-acid sites of formula Al—F or AlF2. The supports are prepared by a method comprising reaction of the surface —OH radicals with a functionalisation agent followed by fluorination.
Our copending application EP 10195224.0 describes activating supports prepared by use of fluorinated alcohols and phenols. Such supports may typically be used in the presence of metallocene complexes for polymerisations performed in both the slurry and gas phase.